The present invention relates to a valve and, more particularly, to a composite valve including a plurality of valve means incorporated as an integral structure therein.
It is often desired to combine a plurality of valves which operate in relation to each other into a single composite valve. By providing such a composite valve, piping between a plurality of separate valves may be omitted and an entirely compact fluid control means is available. A composite valve is particularly effective as a control means to be incorporated in the secondary air supply system for supplying secondary air to the exhaust system of an engine for the purpose of purifying exhaust gases.
When several valves are combined into a composite valve, the design of the exact structure of the composite valve is of course determined in accordance with the particular requirements with regard to the composite valve. However, as a general structure, conventional composite valves have been designed so as to have a housing which is a unitary member or an assembly of several parts and incorporates therein several ports, valve seats, and internal passages required, to which various valve elements and valve actuating means such as diaphragms are individually assembled. In most cases the housings of conventional composite valves are of complicated three-dimensional designs which require complicated manufacturing processes, and, furthermore, they require a large amount of work for assembling individual valves and valve actuating means such as diaphragms into the housings, thereby naturally increasing their cost.